Safety Assessment of the Oral Probiotic Candidates for Infective Endocarditis
Objectives: Oralstreptococci are commonly detected in infective endocarditis. Some Lactobacillus strains have also been reported to cause this disease. We examined whether lactic acid bacteria (LAB) screened as candidates for oral probiotics cause infective endocarditis in an experimental rat endocarditis model.
Methods: We examined 14 oral cavity-derived LAB showing high activity on in vitro functional screening (4 Lactobacillus strains and 10 Streptococcus strains). Each bacterial cells of LAB with 2~5×106 cfu was i.v. administrated into 6-7 endocarditis model rats. Four days after administration, peripheral venous blood and heart containing cardiac vegetations of the animals were collected and serially diluted with physiological saline. Three days after each biological sample was cultured in MRS plate at 37 oC, the number of colonies grown in both plates was counted, and viable cell counts per 1 mL of the blood and of the heart homogenate were calculated.
Results: None of viable cells for Lactobacillus strains (L. crispatus YIT 12319, L. crispatus LBS17-11, L. fermentum YIT 12320, and L. gasseri YIT 12321) were detected in the blood or the cardiac vegetations of rats. Similarly, viable cellsof Streptococcus mitis YIT 12322 were not detected in the blood, and only 1 animal was found to harbor this strain in the cardiac vegetations. Therefore, it was concluded that these strains cause no endocarditis in rats. In contrast, other strains were considered to be causative because a large number of the administered bacteria were found in the vegetations of all rats.
Conclusions: L. crispatus YIT 12319, L. crispatus LBS17-11, L. fermentum YIT 12320, L. gasseri YIT 12321, and Streptococcus mitis YIT 12322 were selected as candidates for oral probiotics to cause no infective endocarditis in an experimental rat endocarditis model.
Division: Japanese Division Meeting
Meeting:2012 Japanese Division Meeting (Niigata, Japan) Location: Niigata, Japan
Year: 2012 Final Presentation ID: Abstract Category|Abstract Category(s):Scientific Program
Authors
Yamaji, Kazuaki
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Kaneko, Kimiyuki
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Miyazaki, Koji
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Hanada, Nobuhiro
( Tsurumi University, Yokohoma, N/A, Japan
)
Okumura, Takekazu
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Imai, Susumu
( Tsurumi University, Yokohoma, N/A, Japan
)
Terai, Tomohiko
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Nakao, Masumi
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Nagata, Tsuyoshi
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Oosuga, Isamu
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Komatsu, Kayoko
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)
Murakami, Junta
( Yakult Central Institute for Microbiological Research, Tokyo, N/A, Japan
)